Rose plant named Devlass

ABSTRACT

A new and distinct greenhouse rose plant of the tea rose type particularly distinguished by its continuous and profuse production of relatively large high-centered flowers of pure white color from early Spring to Winter under greenhouse culture the flowers being borne singly on strong upright stems of substantial length on a vigorous upright plant having abundant foliage.

BACKGROUND OF THE NEW PLANT

This new variety of rose plant originated as a seedling of a hybridwhich resulted from my crossing of an unnamed and unpatented seedlingwith the variety Angel (U.S. Plant Pat. No. 5,172) as the pollen parentwith the object of producing a long stemmed white hybrid tea rose. Thiscrossing was done at Pleasanton, Calif. and the present seedling wasselected from plants resulting from the planting of the seeds of thesaid hybrid in greenhouse at Pleasanton and the present seedling wasselected by me for propagation because of its profuse production of purewhite flowers of very fine form. Propagation was done at Pleasanton bymeans of budding with such satisfactory results that propagation wascontinued in the same manner through several successive generationswhich thereby demonstrated conclusively that the homogeneity of thisplant could be assured.

DESCRIPTION OF THE DRAWING

My new rose plant is illustrated by the accompanying photographicdrawings which show a three-quarter view of a half opened bloom,three-fourths of a face view of a mature bloom, and a bud, the sepals ofwhich are just beginning to open, the colors shown being as nearly trueto that herein specified as is reasonably possible to obtain byconventional photographic procedures.

DESCRIPTION OF THE NEW VARIETY

The following is a detailed description of my new greenhouse rose plantbased upon observation of plants grown in greenhouse at Watsonville,Calif., the color designations being according to The R.H.S. ColourChart published by The Royal Horticultural Society of London, England.

THE PLANT

Origin: Seedling.

Parentage:

Seed parent.--An unnamed and unpatented seedling.

Pollen parent.--The variety Angel (U.S. Plant Pat. No. 5,172).

Classification:

Botanic.--Hybrid Rose.

Commercial.--Greenhouse Rose.

Form: Upright bush.

Growth: Vigorous and very sturdy.

Branching character: Free branching.

Height: About 70 to 75 cm.

Cane length: About 64 cm.

Foliage:

Quantity.--Abundant.

Number of leaves.--About 7 or 8 before the last flower cut.

Shape of leaf.--Odd pinnate.

Size.--131 mm. long and about 9.6 cm. wide.

Leaflets.--Number: Average 3 or 5. Size: About 65 mm. long and 40 mm.wide. Shape: Oval with denticulate margin. Texture: Leathery. Aspect:Smooth and glossy. Color: Upper side -- Green 137-A. Under side --Yellow-green 144-B. Stipules: Adnate with little hairs. Petiolule: 1 mm.Petioles: Length: About 12 mm. Rachis: Smooth and with a sparse numberof small spines.

Thorns:

Size.--About 1 mm. long.

Color.--Yellow-green 147-D.

THE BUD

Size: Large commercial sized bud.

Diameter.--About 34 mm.

Length.--About 36 mm.

Shape: High centered and pointed.

Opening rate: Slow.

Color of petals:

When sepals first divide.--155-D.

When petals begin to unfurl.--155-B.

Sepals:

Number.--Five.

Shape.--Lanceolate.

Character.--Hooded over the bud until ready to divide and when theflowers open, the sepals curl back.

Color.--Inside -- Greyed green 191-B covered with white hairs. Outside-- Yellow-green 144-C.

Calyx:

Shape.--Funnel-shaped.

Size.--Large and broad.

Splitting.13 Calyx does not split.

Aspect.--Smooth.

Peduncle of flower stem:

Length.--About 108 mm.

Aspect.--Smooth with sparse hairs.

Character.--Rigid and erect.

Color.--Yellow-green 144-A.

THE FLOWER

Blooming habit: Continuous and profusely, from early Spring to Winter,blooming freely under greenhouse conditions.

Size of bloom: Large.

Diameter.--About 12 cm.

Depth.--About 40 mm.

Borne: Singly on strong, erect stems.

Shape:

When bloom first opens.--Cup shaped with high center.

When bloom matures.--A widened cup with high center and petals verynicely imbricated.

Petalage:

Number.--About 41.

Arrangement.--Imbricated.

Form.--Generally oval with ruffled margin and slightly pointed apex.

Texture.--Leathery and soft.

Aspect.--Velvety.

Color.--Outer petals body -- White 155-B. Base -- Green-yellow 1-D.Inside petals body -- 155-D. Base -- Yellow 2- D.

Petaloids:

Number.--About 13.

Size.--20 mm. long and 11 mm. wide.

Color.--White 155-D. Base -- Green-yellow 1-D.

Peduncle:

Length.--About 108 mm.

Color.--Yellow-green 144-A.

Character.--Sturdy and upright, but slightly curving.

Fragrance: Slight.

Discoloration after full bloom: Slight.

Persistance: An average of 6 to 9 days as a cut flower.

Disease resistance: Moderately resistant to mildew, black spots and rustas observed at Pleasanton, Calif.

THE REPRODUCTIVE ORGANS

Stamens:

Number.--About 76.

Arrangement.--Slightly introse.

Anthers.--Size: About 3 mm. Color: Yellow-orange 22-B.

Filaments.--Length: About 8 mm. Color: Yellow-green 154-D.

Pollen.--Color: Yellow-orange 22-B.

Pistils:

Number.--About 156.

Styles.--Length: About 8 mm. Color: Yellow-green 154-D.

Stigmas.--Color: Yellow 8-C.

Character of the ovaries: Oval shaped, slightly flattened on one sideand entirely covered with white hairs.

I claim:
 1. The new and distinctive greenhouse rose substantially asherein shown and described, characterized in particular by itscontinuous and profuse production of large white flowers carried onstrong upright stems of medium length, grown from a sturdy, upright,free branching plant with abundant foliage.